I'm also learning Poser 6, and i have a fascination with realistic renders. I've seen some really great ones done with Poser 6, but from what I understand, it really doesn't depend so much on the model as it does the lighting and materials. I don't have any personal examples, but I've seen some extreme realism done with the standard Poser 6 figures, as well as some others. By all means, get M3 if you wish (it is free), but keep in mind the importance of the materails and lighting too. :)